It is assumed that because of the micro-gravity environment in space, a relatively blemish free semiconductor crystal can be more effectively fabricated therein. To fabricate a semiconductor crystal on Earth, the conventional method involves the use of Bridgman-Stockbarger type furnaces which provide for passing a polycrystalline mixture, for example, Gallium Arsenide (GaAs), in an ingot from a high temperature zone to a lower temperature zone. These Bridgman-Stockbarger directional solidification systems use the heating elements in the respective zones for regulating the temperatures therein. To obtain the desired gradients within the furnace, these furnaces are thinly insulated, the heat generated by the heating elements escaping readily into the environment. Accordingly, since it is the respective heating elements which regulate the amount of heat for the different zones of the furnace, a large amount of power, exceeding that which may be technologically and economically generated in space, is needed.
Therefore, to fabricate substantially perfect semiconductor crystals in space, it is imperative that a low power furnace capable of achieving the same end result as a Bridgman-Stockbarger type furnace be used. Furthermore, since this furnace has to be launched into space, it has to be structurally sound.
Accordingly, it is an object of the present invention to provide a low power furnace which is capable of creating precise temperature gradients in space for performing directional solidification of semiconductor crystals.
It is another object of the present invention to provide for a structurally sound furnace which is capable of withstanding the rigor of being launched into space.
A third object of the present invention is to minimize the length of the furnace thereby minimizing weight and volume for launch and operation in space.